The present invention relates to a method of preparing zeolite crystals with a pore system of straight mesopores. Zeolites find widespread use as heterogeneous catalysts. In many applications it is a problem that zeolites only have micropores, since this imposes diffusion limitations on the reaction rate. Several attempts to provide zeolitic crystals with a mesoporous system have been made in the past. One possibility is to lower the crystal size of the zeolite (Madsen C. Jacobsen, C. J. H., Chem.Comm. (1999) (673)) and another possibility is to use mesoporous MCM-41 type materials (e.g. Beck, J. S. et al. J.Am.Chem.Soc. Vol.114 (1992) 10834), both articles of which are incorporated herein by reference. However, MCM-41 type materials only exhibit a strict two-dimensional order and consequently do not posses the same acidity as zeolites with three-dimensional order.
This invention provides a method for preparing zeolite single crystals with a tuneable pore system of straight mesopores through the individual zeolite crystals.
The invention provides also zeolite single crystals and hence catalytic material with straight mesopores prepared according to the method of the invention.
The invention provides furthermore activated catalytic material comprising zeolite single crystals with straight mesopores that have been subjected to dealumination and/or ion-exchange.